/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package ai.platon.pulsar.skeleton.crawl.filter

/**
 * Interface used to limit which URLs enter AppConstants. Used by the injector and the
 * db updater.
 */
interface CrawlUrlFilter {
    /*
     * Interface for a filter that transforms a URL: it can pass the original URL
     * through or "delete" the URL by returning null
     */
    fun filter(url: String): String?

    fun isValid(urlString: String): Boolean {
        return filter(urlString) != null
    }
}
